import * as Notifications from 'expo-notifications';
import { Redirect, Tabs } from 'expo-router';
import { useCallback, useEffect, useMemo, useState } from 'react';

import { HapticTab } from '@/components/haptic-tab';
import { IconSymbol } from '@/components/ui/icon-symbol';
import { Colors } from '@/constants/theme';
import { useColorScheme } from '@/hooks/use-color-scheme';
import { fetchMatrixUnreadCounts } from '@/src/lib/api';
import { useAuth } from '@/src/providers/auth-provider';

export default function TabLayout() {
  const colorScheme = useColorScheme();
  const { activeTenantId, isBootstrapping, token, requiresTenantSelection } = useAuth();
  const [communicationUnread, setCommunicationUnread] = useState(0);

  const refreshCommunicationUnread = useCallback(async () => {
    if (!token || requiresTenantSelection) {
      setCommunicationUnread(0);
      await Notifications.setBadgeCountAsync(0);
      return;
    }

    try {
      const unread = await fetchMatrixUnreadCounts(token);
      const total = Object.values(unread).reduce((sum, room) => sum + (room.count || 0), 0);
      setCommunicationUnread(total);
      await Notifications.setBadgeCountAsync(total);
    } catch {
      // Badge loading must not block tab navigation.
    }
  }, [requiresTenantSelection, token]);

  useEffect(() => {
    void refreshCommunicationUnread();

    if (!token || requiresTenantSelection) return undefined;

    const id = setInterval(() => void refreshCommunicationUnread(), 30000);
    return () => clearInterval(id);
  }, [activeTenantId, refreshCommunicationUnread, requiresTenantSelection, token]);

  const communicationBadge = useMemo(() => {
    if (!communicationUnread) return undefined;
    return communicationUnread > 99 ? '99+' : communicationUnread;
  }, [communicationUnread]);

  if (isBootstrapping) {
    return null;
  }

  if (!token) {
    return <Redirect href="/login" />;
  }

  if (requiresTenantSelection) {
    return <Redirect href="/tenant-select" />;
  }

  return (
    <Tabs
      screenOptions={{
        tabBarActiveTintColor: Colors[colorScheme ?? 'light'].tint,
        headerShown: true,
        tabBarButton: HapticTab,
      }}>
      <Tabs.Screen
        name="index"
        options={{
          title: 'Dashboard',
          tabBarIcon: ({ color }) => <IconSymbol size={24} name="house.fill" color={color} />,
        }}
      />
      <Tabs.Screen
        name="tasks"
        options={{
          title: 'Aufgaben',
          tabBarIcon: ({ color }) => <IconSymbol size={24} name="checklist" color={color} />,
        }}
      />
      <Tabs.Screen
        name="projects"
        options={{
          title: 'Projekte',
          tabBarIcon: ({ color }) => <IconSymbol size={24} name="folder.fill" color={color} />,
        }}
      />
      <Tabs.Screen
        name="communication"
        options={{
          title: 'Kommunikation',
          tabBarBadge: communicationBadge,
          tabBarBadgeStyle: {
            backgroundColor: '#ef4444',
            color: '#ffffff',
            fontSize: 11,
            fontWeight: '800',
          },
          tabBarIcon: ({ color }) => <IconSymbol size={24} name="message.fill" color={color} />,
        }}
      />
      <Tabs.Screen
        name="time"
        options={{
          title: 'Zeit',
          tabBarIcon: ({ color }) => <IconSymbol size={24} name="clock.fill" color={color} />,
        }}
      />
      <Tabs.Screen
        name="explore"
        options={{
          title: 'Mehr',
          tabBarIcon: ({ color }) => <IconSymbol size={24} name="ellipsis.circle.fill" color={color} />,
        }}
      />
    </Tabs>
  );
}